Polyurethane rigid foam materials are used as insulating materials in the construction sector, more specifically in the construction of high-rise buildings and cold-storage houses, and in transportation. However, polyurethane rigid foam materials are combustible because of their chemical composition, and the use thereof for many purposes is thus limited or even becomes impossible.
For reducing the flammability of polyurethane rigid foam materials there are generally employed additive fire-protecting agents based on halogen/phosphorus compounds so that the flammability standard test of DIN 4102/B2, normally flammable, will be fulfilled. However, the additive fire-protecting agents known for that purpose such as, for example, tris-chloroethylphosphate or trisdichloropropylphosphate, have very disadvantageous properties. Upon thermal load they tend to migrate out of the polyurethane rigid foam materials so that no permanent fire-protection is provided. Also, when used, they may be hydrolytically decomposed by moisture, in which reactions corrosive decomposition products may be formed. In addition, the use of additive fire-protecting agents in part results in a significant deterioration of the mechanical properties of the polyurethane foam materials admixed therewith.
It has been known, for example, from Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd edition, volume 10, 1980, page 391, to employ reactive halogen compounds, such as, e.g., dibromoneopentylglycol or halogenated dialcohols in combination with additive phosphorus compounds. However, there is a drawback inherent to the use of such combinations in that the non-reactive portion will migrate and the halogen compounds will not remain dissolved in the polyol component. Said combinations are not storage stable and, therefore, not usable for pre-formulated systems.
Thus, it is the primary object of the present invention to provide a fire-protective formulation for polyurethane rigid foam materials, which formulation reacts with the foam components, is soluble in the polyol component (generally designated as the component A) and will remain permanently stable so that the drawbacks as mentioned above do not occur.